Can we get rid of external css file?

[jqueryisamonad]

Is it possible to move all styles from an external css file inside the component?

Having an external css file makes bundling a bit more complicated in cases where we want to embed all the styles in the script (embeddable widgets, custom elements, etc)

Also, vite doesn't work well with external css files in "library" mode vitejs/vite#1579

[wobsoriano]

Thanks for the PR!

Fixed in #12